The present invention relates to a wheel construction and more specifically the invention relates to wheels for use on roller skates or the like.
These wheels generally consist of a bearing journaling the wheel to an axle and a wheel cover or mantel surrounding a reinforcing ring of a harder material. Typically in these known wheel assemblies, the mantle is of a uniform cross section through substantially its entire width so that it has the same radial spring action or resilience over this width. By reason of this construction, it has been found that the wheel has limited maneuverability. More specifically, in application such as in roller skates, skateboards or the like, a certain differential action is needed between the wheel mantle and the track or roadway to effect cornering. This limitation is due directly to the even radial spring action of the wheel mantle.
Better turning, cornering and braking characteristics are produced when the resilient mantle or cover of the wheel has a greater elastic resilience at one or both axial ends than at its central portion. In order to attain this desired uneven spring action of the resilient mantle or cover, the mantle can be mounted so that it protrudes axially at one or both sides past the more rigid supporting ring of the bearing. This spring action can also be achieved by forming the mantle with conical chambers or circular indentations in end faces. In order to achieve this flexibility, a relatively stiff and hard material must be provided for the wheel mantle which is able to withstand the high bending strain but which no longer has the required shock absorbing and traction capacities on the track or roadway. Thus with the unavoidable wear of the wheel mantle during the operation, the mantle is weakened on its flexible sides so that the spring action characteristics of the wheel mantle continuously change whereby the wheel lacks the required constant uniform riding characteristics.
It is also known to provide a wheel for skateboards wherein the mantle is molded on one side with a plastic of a lesser hardness than in its middle and on its opposite axial end. Two different molding materials must thus be used to manufacture this type of wheel mantle. This technique requires relatively complicated casting tools with many parts. Consequently it has been found that this type of wheel is relatively uneconomical to produce.
With the above in mind, an object of the present invention is to provide an improved wheel for roller skates, skateboards and similar equipment which is characterized by novel features of construction and arrangement including a wheel mantle with increased resilience on both axial ends, which resilience does not materially or significantly change with wear during operation. The wheel construction, therefore, is characterized by good shock absorbing capacity and is relatively economical to manufacture.